My Home Ideas

Special Offers

Be the first to know about This Old House contests, sweepstakes, and events and receive special offers and promotions from your favorite home improvement brands. We'll even send you regular reminders to enter our sweepstakes.

If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Water system leaks?

I have a question regarding the water system in my house. I live in a small city outside of Sacramento, California. For the past two years, Iíve been dealing with a city organization involved with water conservation. Now, Iím a big proponent for conserving our natural resources, but I donít believe Iím getting the correct story from these folks and wanted to get some other opinions before I go and spend a lot of money for someone to tell me what I think is true.

For the past couple of years around spring time, Iíve been getting a notice from the Water Conservation Department regarding excess water on my sidewalk, which is true. I live at the bottom of a sloped street and have other issues that indicate that my property is sensitive to how my neighbors water their yards. But that is a separate issue and not the question that I want to ask you now. But, it is the reason that I became involved with the Water Conservation Department.

After the first notice a couple of years ago, the Water Conservation Department wanted to find out the source of this excess water and I agreed. And, because I had not yet turned on my landscape watering system since turning it off during the winter, they wanted to check my water system in my house to make sure there were no leaks.

So, they connected a pressure gauge to my hose bib and turned on the water. The pressure came up to around 70 psi. Then they turned off the gate valve that connects my home to the city water system. Then, we watched as the pressure on the pressure gauge dropped to 60 to 65 psi. They said that this is a true indication that I have a water leak somewhere in my home. This was a concern to me so I starting checking around with local plumbing supply stores as well as the Internet.

What I took away from the information that I got was that the true best way to check for water leaks (not where the leaks might be located if the system does have a leak) was to (1) make sure all of my hose bibs and indoor faucets are shut off and (2) make sure any other appliances that use water like ice makers or washing machines are shutoff. Then go to the source of the city water and find the water meter that measures the water that comes in my home. I made a note of the values on the meter (both the odometer like numbers that measure full gallons and the dial that measure fractions of a gallon) along with the location of the small triangle that turns around when the least bit of water flows through the meter.

I left the house for 8 hours and when I came back, absolutely nothing had changed on the water meter values and position of the little triangle. I did this test on 3 different days to make sure I would get consistent results and got the same results every time.

So this year rather than waiting for the Water Conservation Department to contact me, I contacted them to see if I could finally put this issue to rest. But, they said that their way of determining if a home water system leaks is the proper way. And, that the leak in my home was small enough to allow water to get past the water meter and not be measured. But also, the leak was large enough to cause a large amount of water to cover my sidewalk. This, of course, did not make any sense to me at all.

By the way, I did contact the Water Department just recently and had them come out and check that the water meter was functioning properly. They did and found no problems with the water meter.

So here is my question. Am I correct in my way in to determine if I have a water leak? If so, do you agree that I donít have a water leak? Thanks very much in advance for your help.

Re: Water system leaks?

You mention that you are seeing water on the sidewalk outside and did not mention that you are seeing any water inside the house. I'm assuming you aren't seeing water stains, toilet running, sink dripping, etc. The water on the sidewalk could indeed be from run-off from other properties or even from groundwater rising up during a rainy times. You say however that you have some sort of irrigation system. It is possible that the valve that is controlling that is not fully closed or is leaking. Perhaps in the winter when the ground is frozen you do not see any water but in the spring when it thaws you get the water coming out. I would think though that a leak that is big enough to wet the sidewalk would be big enough to make the meter register. When they tested the pressure it could be possible that something came on and drew some water (ice maker, water heater, etc).

The other thing that might be occurring is that the pipe coming into the house from the water main is leaking and that would not show up on the water meeter but could (and don't quote me on this one) possibly cause the drop in pressure when the main was shut off at the street.

Hope that helps you out a little as I'm not a plumber there may be some others on the forum that have some more insight.

Re: Water system leaks?

The "Hydrostatic pressure test" is an accurate test to determine if a water line is leaking. This type of test is conducted on new water main lines before they are put into service, the main is pressured up to 200 psi and must hold for 2 hours.
By putting a gauge on your hose bib and turning off the main valve, they conducted a test against every valve and fixture in your home,a small drip or leak anywhere in your home would cause the pressure to drop at the gauge.

Did the pressure stabilize or did it continue to drop?

How long was the duration of the test that was conducted?

You can check to see if the leak is between the meter and the house by doing the same 8 hour test that you have done, you need to shut off the main valve at the house and then the valve at the meter, when you return turn on the valve at the meter while watching the leak indicator on the meter, if it moves the water that leaked out is being replaced, indicating a leak in your service line.

Some water meters will allow a small amount of water to pass and not show any movement in the leak indicator, however enough water to make up the amount that has leaked out should move the leak indicator.

Re: Water system leaks?

You got 2 good answers, but here are other ideas:
1. Are you on a slab? if yes, you may have water supply lines under the slab, assuming they were laid to code. If you do, they may be copper. With time, minerals can eat away and cause tiny holes in copper, causing consistent leaks under the slab. If that's the case, it can be repaired. I would repipe (in the walls and attic, abandoning the old lines), rather than repair. The reason: if a hole happens in one spot, other holes will appear in other areas too.
2. If your house is a two story, you have more water stored in the pipes, and when you run your test, more water may leaks under the slab.
3. Are you sure the water valves (at the meter and the main) are in 100% working condition and stop the water completely? If the meter shut off valve allows undetected water to go by, the water department must replace it.
4. If you determine that you absolutely have no leak, and if there are houses on your block higher than yours, the water may be coming from there.
Keep us posted.

Re: Water system leaks?

As Blake said, the hydrostatic test is done over a period of time, and with valves shut. If you are wanting to see if appliances such as toilets are leaking water, it will not be of any use. If the city has water or sewer lines near the sidewalk those should be tested. The water can also be tested for fluorine, chlorine, and fecal coliform to see where it came from. In a piping system with no entrapped air, a temperature change of only a couple of degrees can make a large change in pressure, so the hydrostatic test is not accurate unless the plumbing system piping has a stable temperature also. Where was the gate valve located? Most meters have a plug valve on their inlet. Is that what you are referring to? I would think a leak large enough to be seen on the sidewalk would drop the guage pressure to 0 PSI in just a minute or two.

Re: Water system leaks?

The point that you are only seeing leak in the spring time before turning on your landscaping systems is intereasting. Is this the only time you see water on the sidewalk?

If the answer is yes, how can you have a leak that doesn't leak ALL the time? You can't. There is no leak.

If the answer is no, does your house have another shutoff for the house either just outside (withing 5' of the outside wall) or just inside (isolating the entire house water supply)? You might have a leak between the meter and the house. Not one of your fixtures, but the underground supply pipe to the house.

Re: Water system leaks?

The point that you are only seeing leak in the spring time before turning on your landscaping systems is intereasting. Is this the only time you see water on the sidewalk?

If the answer is yes, how can you have a leak that doesn't leak ALL the time? You can't. There is no leak.

If the answer is no, does your house have another shutoff for the house either just outside (withing 5' of the outside wall) or just inside (isolating the entire house water supply)? You might have a leak between the meter and the house. Not one of your fixtures, but the underground supply pipe to the house.